[EN1991-1-4] This guide explains how to calculate the wind force acting on circular bridge piers. The wind force is determined using factors such as the force coefficient, structural factor, peak velocity pressure at the reference height, and the exposed reference area. The guide also considers the influence of surface roughness and Reynolds number, ensuring accurate estimation of wind loads on circular bridge piers.

The length refers to the total vertical height of the structural element being analyzed, such as a circular pier. This measurement is crucial for determining the reference area exposed to wind loads.

Length of the circular pier being considered

The diameter represents the width of the circular bridge pier. It is the horizontal measurement across the pier's cross-section and is used to calculate the reference area for wind load analysis.

Diameter of circular pier

This menu allows users to select the type of surface material for the structure. Different surface types, such as smooth concrete, rough concrete, and various metals, affect wind resistance and load calculations.

Surface type selection

The reference height is the maximum height above ground for the section being considered. This height is used in wind load calculations to determine the peak wind velocity and other wind-related forces acting on the structure.

Reference height above ground

This section allows the user to choose the appropriate terrain category based on the characteristics of the surrounding area. Terrain categories are used to define the roughness of the ground, which affects wind speed calculations. Options typically range from open terrain with low vegetation to urban environments with numerous obstacles.

Terrain category selection

The fundamental wind velocity is the baseline 10-minute mean wind speed measured at a height of 10 meters above open terrain with minimal vegetation and few obstacles. It is the starting point for calculating the basic wind velocity, before applying any adjustments for wind direction or season. The value is typically provided in national standards.

Fundamental wind velocity

The mean return period is the average time interval over which a specific wind event (like a wind speed) is expected to be exceeded once. A mean return period of 50 years indicates that the wind speed is likely to be exceeded once every 50 years on average.